Improvement in screw-drivers



UNITED STATES VPATENT OFFICE.

WILLIAM F. PATTERSON, OF BOSTON, MASSACHUSETTS.

IMPROVEMENT IN SCREW-DRIVERS.

Specification forming part of Letters Patent No. 160,543, dated March 9, 1875; application led December 15, 1874.

' ing, forming a part of this specification, in

which- Figure 1 isa vertical section showing the clamp, and Fig. 2 an isometrical perspective view.

Like letters of reference indicate corresponding parts in the different figures of the draw- Y ing.

My invention relates to that class of screwdrivers which are provided with adjustable .f and detachable blades; and consists in a novel construction and arrangement ofthe parts, as hereinafter more fully set forth and claimed, as au improvement upon the patent granted to me February 24, 1874, No. 147,785.

In the drawing, A represents the handle; B, the shank or fixed blade; Gr, the step; O, the clamp; E, the clamp-nut; and F, the auxiliary or adjustable blade. The step G is provided with a thumb-screw, H, and shoulder or ledge and is designed to rest upon a shoulderv formed on the main blade B, near the handle A. The clamp O has a central aperture, J, enablin g it to be passed over the blades F B very easily, and is provided with the tapering segmental wall-screws D K. The screw K is rigidly attached to the body of the clamp, and the screw D to the spring I, one end of which is secured to the clamp, and the other working freely in a slot through the side of the same.,

In using my improved screw-driver the step G is rst passed over the blade B, and secured thereto by means of the screw H. The blade F is then adjusted upon the shoulder m, and both blades of the driver inserted in the aperture J of the clamp C, as shown in Fig. 2. The nut E is now turned onto the screws D K, bending the spring I, to which the screw D is attached. inwardly, as shown in Fig. 1, thus forcing it aga-inst the blades, and securing or clamping them together in a manner which will be readily understood without a more explicit description.

It will be obvious that the step G may be adjusted so as to cause the blade F to project beyond the blade B, as required, and also that the loose blades may be easily reversed.

Having thus explained my invention, what I claim as my invention is- The screw-driver herein described, consisting of the blade B, adjustable step G, provided with screw H and shoulder x, reversible blade F, detachable clamp O, provided with the sectional screws D K and spring I, and the clampnut E, when constructed and arranged to operate substantially as and for the purpose specified.

VILLIAM F. PATTERSON.

Witnesses:

C. A. SHAW, H. E. METoALF. 

